[1] [1] Goldsborough J P. Beat frequencies between modes of a concave-mirror optical resonator. Appl. Opt., 1964, 3(2):267～275

[2] [2] Wang Z, Chen T, Ding Y et al.. High-power CO2 blending mode laser beam propagation and focus on account of phase shifts. Proc. SPIE, 1998, 3268:18～27

[3] [3] Kogelink H. Matching of optical modes. Bell. Syst. Tech. J., 1964, 43:334～337

[5] [5] Siegman A E. Analysis of laser beam quality degradation caused by quartic phase aberrations. Appl. Opt., 1993, 32(30):5893～5901

[7] [7] Siegman A E. New developments in laser resonators. Proc. SPIE, 1992, 1990:2～14

[8] [8] Ruff J A, Siegman A E. Measurement of beam quality degradation due to spherical aberration in a simple lens. Opt. & Quant. Electron., 1994, 26(6):629～632

[9] [9] Yoshida A, Asakura T. Propagation and focusing of Gaussian laser beams beyond conventional diffraction limit. Opt. Commun., 1996, 123(4/6):694～704